noun
helmet cape; arrow-protecting back cloth
Historical term for a cloth covering worn on the back of armor to protect against arrows during battle.
戦国時代の武士は、背中に母衣を付けて矢を防いだ。
Warriors in the Sengoku period wore a horo on their backs to protect against arrows.
The reading ほろ is a gikun (meaning-based reading) for the kanji 母衣. The origin of the word itself is uncertain.